The Meddle cover is a literal visual pun.

Yes, it’s an ear underwater with a hand reaching out to touch it. The band and Hipgnosis (the design studio) wanted to illustrate the word “meddle” — interfering with something. So they chose an ear (listening / sound) and a hand (meddling / touching). It’s not a deep mystery, just a clever one-liner in image form.

The photo was shot in a swimming